Various types of electric power tools are commonly used in construction, home improvement, outdoor, and do-it-yourself projects. Conventional power tools generally fall into two categories—corded power tools that are powered by an AC power source, e.g., an AC mains line, and cordless power tools that are powered by one or more DC power sources, e.g., a rechargeable battery pack.
The corded power tools generally are used for heavy duty applications that require high power and/or long runtimes, such as heavy duty sawing, heavy duty drilling and hammering, and heavy duty metal working. However, as their name implies, corded power tools require the use of a cord that can be connected to an AC power source. In many applications, such as on construction sites, it is not convenient or practical to find a continuously available AC power source and/or AC power must be generated by a portable power supply such as a generator, e.g. gas powered generator.
The cordless power tools generally are used for lighter duty applications that require low or medium power and/or short runtimes, such as light duty sawing, light duty drilling, and fastening. As cordless tools tend to be more limited in their power and/or runtime, they have not generally been accepted by the industry for all applications. They are also limited by weight since the higher capacity batteries tend to have greater weight, creating an ergonomic disadvantage.
As the desire for more powerful cordless power tools increases and as more powerful power tools are presented to the marketplace correspondingly more powerful battery packs to power the more powerful cordless tools must be developed. In order to provide more powerful battery packs, either additional cells are added to the battery pack or larger format cells are used in the battery pack. Under either circumstance the battery pack will increase in size and weight. The increased size and weight of the battery pack will place additional strain on the battery pack housing and mechanical interface system of the battery pack, particularly the rails of a rail and groove system common in slide-type battery packs.